Tamper-evident closures of the type employing an annular tamper-evident ring interconnected to a threaded cap through break-away tabs are well known in the art. For example, in the bottling of soda pop it is common to actually roll a stamped metal member onto the threaded neck of a bottle to form a closure therefor. The lower edge of the closure can be wrapped under a peripheral rim associated with the neck of the bottle, and a plurality of spaced-apart cuts can be formed about the periphery of the closure, in an area below the bottle threads and above the rim, to define spaced-apart tabs that divide the closure into an upper cap and lower tamper-evident ring.
Rolled metal closures of the type described above often have proven unreliable in operation. In fact, almost anyone who purchases soda on a regular basis encounters bottles in which the tabs interconnecting the cap to the tamper-evident ring do not separate when the cap is turned to open it. When this occurs, the lower in-turned edge of the cap that is wrapped under the rim on the bottle can actually prevent physical separation of the cap from the bottle, unless either the in-turned edge is pried away from the rim, or the tabs are manually cut with a knife or other instrument. Moreover, if the cap is removed without separation of the tamper-evident ring, the closure can be reattached to the bottle without providing any visible indication that the bottle was ever opened. This completely defeats the intended reason for providing the tamper-evident ring.
It also is known in the art to mold a closure having a threaded plastic cap with an annular tamper-evident ring integral therewith, the ring being interconnected to the threaded cap through a series of break-away tabs spaced about the entire periphery of the closure. The tamper-evident ring is molded below the threaded cap, either coaxial with the cap or slightly offset in a lateral direction. In either case, the tamper-evident ring is intended to be spaced-apart from the lower surface of the cap, and retained in proper position relative to said cap solely by the break-away tabs. In order to maintain the closure in a functional condition, these break-away tabs need to be able to withstand the vertical and rotational forces imposed upon them, without breaking, as the closure is being secured to a container. This generally necessitates very careful handling of the closure in special capping equipment. Stating this another way, the sole support for the tamper-evident ring is the interconnecting tabs, which, if properly formed, do not provide a great deal of interconnecting strength. Therefore, these tabs may not be able to withstand the forces imposed upon them in conventional capping equipment; thus necessitating the use of special capping equipment.
It is not uncommon in the formation of the above-described plastic, tamper-evident closures to experience flashing in the molding operation. If this occurs, plastic bridges can be formed between the break-away tabs to thereby form an excessively strong bridge between the cap and ring, and thereby prevent easy separation of the ring from the cap as the cap is being rotated to open the container. This can either prevent easy removable of the cap from the container, or can cause separation of the cap and ring as a single unit. In the latter case there will be no visible indication that the container had been opened once the closure is reattached to the container.
In all of the above-described systems, a plurality of break-away tabs are provided about the entire outer periphery of the closure to interconnect a threaded cap member to a tamper-evident ring. This sometimes provides a very strong interconnection which imposes a great deal of resistance to the separation of the cap from the ring. In these cases it virtually is impossible for individuals inflicted with arthritis of the hands, or similar debilitating conditions, from being able to remove the closure.
The present invention is intended to overcome the above-described deficiencies encountered in the prior art systems.